Staging: add comedi core

This adds the Comedi core to the staging tree.
This is a data acquision infrastructure for Linux, providing a common
interface for these types of drivers.

Taken directly from the comedi git tree, with only minor tweaks
by Greg to get it to build properly within the kernel tree.

From: David Schleef <ds@schleef.org>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Shawn Bohrer <shawn.bohrer@gmail.com>
Signed-off-by: Frank Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 846 insertions, 0 deletions

diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
new file mode 100644
index 00000000000..06372b227bb
--- /dev/null
+++ b/drivers/staging/comedi/drivers.c
@@ -0,0 +1,846 @@
+/*
+    module/drivers.c
+    functions for manipulating drivers
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#define _GNU_SOURCE
+
+#define __NO_VERSION__
+#include "comedi_fops.h"
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/fcntl.h>
+#include <linux/delay.h>
+#include <linux/ioport.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include "comedidev.h"
+#include "wrapper.h"
+#include <linux/highmem.h>	/* for SuSE brokenness */
+#include <linux/vmalloc.h>
+#include <linux/cdev.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/io.h>
+#include <asm/system.h>
+
+static int postconfig(comedi_device * dev);
+static int insn_rw_emulate_bits(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data);
+static void *comedi_recognize(comedi_driver * driv, const char *name);
+static void comedi_report_boards(comedi_driver * driv);
+static int poll_invalid(comedi_device * dev, comedi_subdevice * s);
+int comedi_buf_alloc(comedi_device * dev, comedi_subdevice * s,
+	unsigned long new_size);
+
+comedi_driver *comedi_drivers;
+
+int comedi_modprobe(int minor)
+{
+	return -EINVAL;
+}
+
+static void cleanup_device(comedi_device * dev)
+{
+	int i;
+	comedi_subdevice *s;
+
+	if (dev->subdevices) {
+		for (i = 0; i < dev->n_subdevices; i++) {
+			s = dev->subdevices + i;
+			comedi_free_subdevice_minor(s);
+			if (s->async) {
+				comedi_buf_alloc(dev, s, 0);
+				kfree(s->async);
+			}
+		}
+		kfree(dev->subdevices);
+		dev->subdevices = NULL;
+		dev->n_subdevices = 0;
+	}
+	if (dev->private) {
+		kfree(dev->private);
+		dev->private = NULL;
+	}
+	dev->driver = 0;
+	dev->board_name = NULL;
+	dev->board_ptr = NULL;
+	dev->iobase = 0;
+	dev->irq = 0;
+	dev->read_subdev = NULL;
+	dev->write_subdev = NULL;
+	dev->open = NULL;
+	dev->close = NULL;
+	comedi_set_hw_dev(dev, NULL);
+}
+
+static void __comedi_device_detach(comedi_device * dev)
+{
+	dev->attached = 0;
+	if (dev->driver) {
+		dev->driver->detach(dev);
+	} else {
+		printk("BUG: dev->driver=NULL in comedi_device_detach()\n");
+	}
+	cleanup_device(dev);
+}
+
+void comedi_device_detach(comedi_device * dev)
+{
+	if (!dev->attached)
+		return;
+	__comedi_device_detach(dev);
+}
+
+int comedi_device_attach(comedi_device * dev, comedi_devconfig * it)
+{
+	comedi_driver *driv;
+	int ret;
+
+	if (dev->attached)
+		return -EBUSY;
+
+	for (driv = comedi_drivers; driv; driv = driv->next) {
+		if (!try_module_get(driv->module)) {
+			printk("comedi: failed to increment module count, skipping\n");
+			continue;
+		}
+		if (driv->num_names) {
+			dev->board_ptr = comedi_recognize(driv, it->board_name);
+			if (dev->board_ptr == NULL) {
+				module_put(driv->module);
+				continue;
+			}
+		} else {
+			if (strcmp(driv->driver_name, it->board_name)) {
+				module_put(driv->module);
+				continue;
+			}
+		}
+		//initialize dev->driver here so comedi_error() can be called from attach
+		dev->driver = driv;
+		ret = driv->attach(dev, it);
+		if (ret < 0) {
+			module_put(dev->driver->module);
+			__comedi_device_detach(dev);
+			return ret;
+		}
+		goto attached;
+	}
+
+	// recognize has failed if we get here
+	// report valid board names before returning error
+	for (driv = comedi_drivers; driv; driv = driv->next) {
+		if (!try_module_get(driv->module)) {
+			printk("comedi: failed to increment module count\n");
+			continue;
+		}
+		comedi_report_boards(driv);
+		module_put(driv->module);
+	}
+	return -EIO;
+
+attached:
+	/* do a little post-config cleanup */
+	ret = postconfig(dev);
+	module_put(dev->driver->module);
+	if (ret < 0) {
+		__comedi_device_detach(dev);
+		return ret;
+	}
+
+	if (!dev->board_name) {
+		printk("BUG: dev->board_name=<%p>\n", dev->board_name);
+		dev->board_name = "BUG";
+	}
+	smp_wmb();
+	dev->attached = 1;
+
+	return 0;
+}
+
+int comedi_driver_register(comedi_driver * driver)
+{
+	driver->next = comedi_drivers;
+	comedi_drivers = driver;
+
+	return 0;
+}
+
+int comedi_driver_unregister(comedi_driver * driver)
+{
+	comedi_driver *prev;
+	int i;
+
+	/* check for devices using this driver */
+	for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
+		struct comedi_device_file_info *dev_file_info = comedi_get_device_file_info(i);
+		comedi_device *dev;
+
+		if(dev_file_info == NULL) continue;
+		dev = dev_file_info->device;
+
+		mutex_lock(&dev->mutex);
+		if (dev->attached && dev->driver == driver) {
+			if (dev->use_count)
+				printk("BUG! detaching device with use_count=%d\n", dev->use_count);
+			comedi_device_detach(dev);
+		}
+		mutex_unlock(&dev->mutex);
+	}
+
+	if (comedi_drivers == driver) {
+		comedi_drivers = driver->next;
+		return 0;
+	}
+
+	for (prev = comedi_drivers; prev->next; prev = prev->next) {
+		if (prev->next == driver) {
+			prev->next = driver->next;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static int postconfig(comedi_device * dev)
+{
+	int i;
+	comedi_subdevice *s;
+	comedi_async *async = NULL;
+	int ret;
+
+	for (i = 0; i < dev->n_subdevices; i++) {
+		s = dev->subdevices + i;
+
+		if (s->type == COMEDI_SUBD_UNUSED)
+			continue;
+
+		if (s->len_chanlist == 0)
+			s->len_chanlist = 1;
+
+		if (s->do_cmd) {
+			BUG_ON((s->subdev_flags & (SDF_CMD_READ |
+				SDF_CMD_WRITE)) == 0);
+			BUG_ON(!s->do_cmdtest);
+
+			async = kzalloc(sizeof(comedi_async), GFP_KERNEL);
+			if (async == NULL) {
+				printk("failed to allocate async struct\n");
+				return -ENOMEM;
+			}
+			init_waitqueue_head(&async->wait_head);
+			async->subdevice = s;
+			s->async = async;
+
+#define DEFAULT_BUF_MAXSIZE (64*1024)
+#define DEFAULT_BUF_SIZE (64*1024)
+
+			async->max_bufsize = DEFAULT_BUF_MAXSIZE;
+
+			async->prealloc_buf = NULL;
+			async->prealloc_bufsz = 0;
+			if (comedi_buf_alloc(dev, s, DEFAULT_BUF_SIZE) < 0) {
+				printk("Buffer allocation failed\n");
+				return -ENOMEM;
+			}
+			if (s->buf_change) {
+				ret = s->buf_change(dev, s, DEFAULT_BUF_SIZE);
+				if (ret < 0)
+					return ret;
+			}
+			comedi_alloc_subdevice_minor(dev, s);
+		}
+
+		if (!s->range_table && !s->range_table_list)
+			s->range_table = &range_unknown;
+
+		if (!s->insn_read && s->insn_bits)
+			s->insn_read = insn_rw_emulate_bits;
+		if (!s->insn_write && s->insn_bits)
+			s->insn_write = insn_rw_emulate_bits;
+
+		if (!s->insn_read)
+			s->insn_read = insn_inval;
+		if (!s->insn_write)
+			s->insn_write = insn_inval;
+		if (!s->insn_bits)
+			s->insn_bits = insn_inval;
+		if (!s->insn_config)
+			s->insn_config = insn_inval;
+
+		if (!s->poll)
+			s->poll = poll_invalid;
+	}
+
+	return 0;
+}
+
+// generic recognize function for drivers that register their supported board names
+void *comedi_recognize(comedi_driver * driv, const char *name)
+{
+	unsigned i;
+	const char *const *name_ptr = driv->board_name;
+	for (i = 0; i < driv->num_names; i++) {
+		if (strcmp(*name_ptr, name) == 0)
+			return (void *)name_ptr;
+		name_ptr =
+			(const char *const *)((const char *)name_ptr +
+			driv->offset);
+	}
+
+	return NULL;
+}
+
+void comedi_report_boards(comedi_driver * driv)
+{
+	unsigned int i;
+	const char *const *name_ptr;
+
+	printk("comedi: valid board names for %s driver are:\n",
+		driv->driver_name);
+
+	name_ptr = driv->board_name;
+	for (i = 0; i < driv->num_names; i++) {
+		printk(" %s\n", *name_ptr);
+		name_ptr = (const char **)((char *)name_ptr + driv->offset);
+	}
+
+	if (driv->num_names == 0)
+		printk(" %s\n", driv->driver_name);
+}
+
+static int poll_invalid(comedi_device * dev, comedi_subdevice * s)
+{
+	return -EINVAL;
+}
+
+int insn_inval(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data)
+{
+	return -EINVAL;
+}
+
+static int insn_rw_emulate_bits(comedi_device * dev, comedi_subdevice * s,
+	comedi_insn * insn, lsampl_t * data)
+{
+	comedi_insn new_insn;
+	int ret;
+	static const unsigned channels_per_bitfield = 32;
+
+	unsigned chan = CR_CHAN(insn->chanspec);
+	const unsigned base_bitfield_channel =
+		(chan < channels_per_bitfield) ? 0 : chan;
+	lsampl_t new_data[2];
+	memset(new_data, 0, sizeof(new_data));
+	memset(&new_insn, 0, sizeof(new_insn));
+	new_insn.insn = INSN_BITS;
+	new_insn.chanspec = base_bitfield_channel;
+	new_insn.n = 2;
+	new_insn.data = new_data;
+	new_insn.subdev = insn->subdev;
+
+	if (insn->insn == INSN_WRITE) {
+		if (!(s->subdev_flags & SDF_WRITABLE))
+			return -EINVAL;
+		new_data[0] = 1 << (chan - base_bitfield_channel);	/* mask */
+		new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel)) : 0;	/* bits */
+	}
+
+	ret = s->insn_bits(dev, s, &new_insn, new_data);
+	if (ret < 0)
+		return ret;
+
+	if (insn->insn == INSN_READ) {
+		data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;
+	}
+
+	return 1;
+}
+
+static inline unsigned long uvirt_to_kva(pgd_t * pgd, unsigned long adr)
+{
+	unsigned long ret = 0UL;
+	pmd_t *pmd;
+	pte_t *ptep, pte;
+	pud_t *pud;
+
+	if (!pgd_none(*pgd)) {
+		pud = pud_offset(pgd, adr);
+		pmd = pmd_offset(pud, adr);
+		if (!pmd_none(*pmd)) {
+			ptep = pte_offset_kernel(pmd, adr);
+			pte = *ptep;
+			if (pte_present(pte)) {
+				ret = (unsigned long)
+					page_address(pte_page(pte));
+				ret |= (adr & (PAGE_SIZE - 1));
+			}
+		}
+	}
+	return ret;
+}
+
+static inline unsigned long kvirt_to_kva(unsigned long adr)
+{
+	unsigned long va, kva;
+
+	va = adr;
+	kva = uvirt_to_kva(pgd_offset_k(va), va);
+
+	return kva;
+}
+
+int comedi_buf_alloc(comedi_device * dev, comedi_subdevice * s,
+	unsigned long new_size)
+{
+	comedi_async *async = s->async;
+
+	/* Round up new_size to multiple of PAGE_SIZE */
+	new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
+
+	/* if no change is required, do nothing */
+	if (async->prealloc_buf && async->prealloc_bufsz == new_size) {
+		return 0;
+	}
+	// deallocate old buffer
+	if (async->prealloc_buf) {
+		vunmap(async->prealloc_buf);
+		async->prealloc_buf = NULL;
+		async->prealloc_bufsz = 0;
+	}
+	if (async->buf_page_list) {
+		unsigned i;
+		for (i = 0; i < async->n_buf_pages; ++i) {
+			if (async->buf_page_list[i].virt_addr) {
+				mem_map_unreserve(virt_to_page(async->
+						buf_page_list[i].virt_addr));
+				if (s->async_dma_dir != DMA_NONE) {
+					dma_free_coherent(dev->hw_dev,
+						PAGE_SIZE,
+						async->buf_page_list[i].
+						virt_addr,
+						async->buf_page_list[i].
+						dma_addr);
+				} else {
+					free_page((unsigned long)async->
+						buf_page_list[i].virt_addr);
+				}
+			}
+		}
+		vfree(async->buf_page_list);
+		async->buf_page_list = NULL;
+		async->n_buf_pages = 0;
+	}
+	// allocate new buffer
+	if (new_size) {
+		unsigned i = 0;
+		unsigned n_pages = new_size >> PAGE_SHIFT;
+		struct page **pages = NULL;
+
+		async->buf_page_list =
+			vmalloc(sizeof(struct comedi_buf_page) * n_pages);
+		if (async->buf_page_list) {
+			memset(async->buf_page_list, 0,
+				sizeof(struct comedi_buf_page) * n_pages);
+			pages = vmalloc(sizeof(struct page *) * n_pages);
+		}
+		if (pages) {
+			for (i = 0; i < n_pages; i++) {
+				if (s->async_dma_dir != DMA_NONE) {
+					async->buf_page_list[i].virt_addr =
+						dma_alloc_coherent(dev->hw_dev,
+						PAGE_SIZE,
+						&async->buf_page_list[i].
+						dma_addr,
+						GFP_KERNEL | __GFP_COMP);
+				} else {
+					async->buf_page_list[i].virt_addr =
+						(void *)
+						get_zeroed_page(GFP_KERNEL);
+				}
+				if (async->buf_page_list[i].virt_addr == NULL) {
+					break;
+				}
+				mem_map_reserve(virt_to_page(async->
+						buf_page_list[i].virt_addr));
+				pages[i] =
+					virt_to_page(async->buf_page_list[i].
+					virt_addr);
+			}
+		}
+		if (i == n_pages) {
+			async->prealloc_buf =
+				vmap(pages, n_pages, VM_MAP,
+				PAGE_KERNEL_NOCACHE);
+		}
+		if (pages) {
+			vfree(pages);
+		}
+		if (async->prealloc_buf == NULL) {
+			/* Some allocation failed above. */
+			if (async->buf_page_list) {
+				for (i = 0; i < n_pages; i++) {
+					if (async->buf_page_list[i].virt_addr ==
+						NULL) {
+						break;
+					}
+					mem_map_unreserve(virt_to_page(async->
+							buf_page_list[i].
+							virt_addr));
+					if (s->async_dma_dir != DMA_NONE) {
+						dma_free_coherent(dev->hw_dev,
+							PAGE_SIZE,
+							async->buf_page_list[i].
+							virt_addr,
+							async->buf_page_list[i].
+							dma_addr);
+					} else {
+						free_page((unsigned long)async->
+							buf_page_list[i].
+							virt_addr);
+					}
+				}
+				vfree(async->buf_page_list);
+				async->buf_page_list = NULL;
+			}
+			return -ENOMEM;
+		}
+		async->n_buf_pages = n_pages;
+	}
+	async->prealloc_bufsz = new_size;
+
+	return 0;
+}
+
+/* munging is applied to data by core as it passes between user
+ * and kernel space */
+unsigned int comedi_buf_munge(comedi_async * async, unsigned int num_bytes)
+{
+	comedi_subdevice *s = async->subdevice;
+	unsigned int count = 0;
+	const unsigned num_sample_bytes = bytes_per_sample(s);
+
+	if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
+		async->munge_count += num_bytes;
+		if ((int)(async->munge_count - async->buf_write_count) > 0)
+			BUG();
+		return num_bytes;
+	}
+	/* don't munge partial samples */
+	num_bytes -= num_bytes % num_sample_bytes;
+	while (count < num_bytes) {
+		int block_size;
+
+		block_size = num_bytes - count;
+		if (block_size < 0) {
+			rt_printk("%s: %s: bug! block_size is negative\n",
+				__FILE__, __FUNCTION__);
+			break;
+		}
+		if ((int)(async->munge_ptr + block_size -
+				async->prealloc_bufsz) > 0)
+			block_size = async->prealloc_bufsz - async->munge_ptr;
+
+		s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
+			block_size, async->munge_chan);
+
+		smp_wmb();	//barrier insures data is munged in buffer before munge_count is incremented
+
+		async->munge_chan += block_size / num_sample_bytes;
+		async->munge_chan %= async->cmd.chanlist_len;
+		async->munge_count += block_size;
+		async->munge_ptr += block_size;
+		async->munge_ptr %= async->prealloc_bufsz;
+		count += block_size;
+	}
+	if ((int)(async->munge_count - async->buf_write_count) > 0)
+		BUG();
+	return count;
+}
+
+unsigned int comedi_buf_write_n_available(comedi_async * async)
+{
+	unsigned int free_end;
+	unsigned int nbytes;
+
+	if (async == NULL)
+		return 0;
+
+	free_end = async->buf_read_count + async->prealloc_bufsz;
+	nbytes = free_end - async->buf_write_alloc_count;
+	nbytes -= nbytes % bytes_per_sample(async->subdevice);
+	/* barrier insures the read of buf_read_count in this
+	   query occurs before any following writes to the buffer which
+	   might be based on the return value from this query.
+	 */
+	smp_mb();
+	return nbytes;
+}
+
+/* allocates chunk for the writer from free buffer space */
+unsigned int comedi_buf_write_alloc(comedi_async * async, unsigned int nbytes)
+{
+	unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
+
+	if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) {
+		nbytes = free_end - async->buf_write_alloc_count;
+	}
+	async->buf_write_alloc_count += nbytes;
+	/* barrier insures the read of buf_read_count above occurs before
+	   we write data to the write-alloc'ed buffer space */
+	smp_mb();
+	return nbytes;
+}
+
+/* allocates nothing unless it can completely fulfill the request */
+unsigned int comedi_buf_write_alloc_strict(comedi_async * async,
+	unsigned int nbytes)
+{
+	unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
+
+	if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) {
+		nbytes = 0;
+	}
+	async->buf_write_alloc_count += nbytes;
+	/* barrier insures the read of buf_read_count above occurs before
+	   we write data to the write-alloc'ed buffer space */
+	smp_mb();
+	return nbytes;
+}
+
+/* transfers a chunk from writer to filled buffer space */
+unsigned comedi_buf_write_free(comedi_async * async, unsigned int nbytes)
+{
+	if ((int)(async->buf_write_count + nbytes -
+			async->buf_write_alloc_count) > 0) {
+		rt_printk
+			("comedi: attempted to write-free more bytes than have been write-allocated.\n");
+		nbytes = async->buf_write_alloc_count - async->buf_write_count;
+	}
+	async->buf_write_count += nbytes;
+	async->buf_write_ptr += nbytes;
+	comedi_buf_munge(async, async->buf_write_count - async->munge_count);
+	if (async->buf_write_ptr >= async->prealloc_bufsz) {
+		async->buf_write_ptr %= async->prealloc_bufsz;
+	}
+	return nbytes;
+}
+
+/* allocates a chunk for the reader from filled (and munged) buffer space */
+unsigned comedi_buf_read_alloc(comedi_async * async, unsigned nbytes)
+{
+	if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
+		0) {
+		nbytes = async->munge_count - async->buf_read_alloc_count;
+	}
+	async->buf_read_alloc_count += nbytes;
+	/* barrier insures read of munge_count occurs before we actually read
+	   data out of buffer */
+	smp_rmb();
+	return nbytes;
+}
+
+/* transfers control of a chunk from reader to free buffer space */
+unsigned comedi_buf_read_free(comedi_async * async, unsigned int nbytes)
+{
+	// barrier insures data has been read out of buffer before read count is incremented
+	smp_mb();
+	if ((int)(async->buf_read_count + nbytes -
+			async->buf_read_alloc_count) > 0) {
+		rt_printk
+			("comedi: attempted to read-free more bytes than have been read-allocated.\n");
+		nbytes = async->buf_read_alloc_count - async->buf_read_count;
+	}
+	async->buf_read_count += nbytes;
+	async->buf_read_ptr += nbytes;
+	async->buf_read_ptr %= async->prealloc_bufsz;
+	return nbytes;
+}
+
+void comedi_buf_memcpy_to(comedi_async * async, unsigned int offset,
+	const void *data, unsigned int num_bytes)
+{
+	unsigned int write_ptr = async->buf_write_ptr + offset;
+
+	if (write_ptr >= async->prealloc_bufsz)
+		write_ptr %= async->prealloc_bufsz;
+
+	while (num_bytes) {
+		unsigned int block_size;
+
+		if (write_ptr + num_bytes > async->prealloc_bufsz)
+			block_size = async->prealloc_bufsz - write_ptr;
+		else
+			block_size = num_bytes;
+
+		memcpy(async->prealloc_buf + write_ptr, data, block_size);
+
+		data += block_size;
+		num_bytes -= block_size;
+
+		write_ptr = 0;
+	}
+}
+
+void comedi_buf_memcpy_from(comedi_async * async, unsigned int offset,
+	void *dest, unsigned int nbytes)
+{
+	void *src;
+	unsigned int read_ptr = async->buf_read_ptr + offset;
+
+	if (read_ptr >= async->prealloc_bufsz)
+		read_ptr %= async->prealloc_bufsz;
+
+	while (nbytes) {
+		unsigned int block_size;
+
+		src = async->prealloc_buf + read_ptr;
+
+		if (nbytes >= async->prealloc_bufsz - read_ptr)
+			block_size = async->prealloc_bufsz - read_ptr;
+		else
+			block_size = nbytes;
+
+		memcpy(dest, src, block_size);
+		nbytes -= block_size;
+		dest += block_size;
+		read_ptr = 0;
+	}
+}
+
+unsigned int comedi_buf_read_n_available(comedi_async * async)
+{
+	unsigned num_bytes;
+
+	if (async == NULL)
+		return 0;
+	num_bytes = async->munge_count - async->buf_read_count;
+	/* barrier insures the read of munge_count in this
+	   query occurs before any following reads of the buffer which
+	   might be based on the return value from this query.
+	 */
+	smp_rmb();
+	return num_bytes;
+}
+
+int comedi_buf_get(comedi_async * async, sampl_t * x)
+{
+	unsigned int n = comedi_buf_read_n_available(async);
+
+	if (n < sizeof(sampl_t))
+		return 0;
+	comedi_buf_read_alloc(async, sizeof(sampl_t));
+	*x = *(sampl_t *) (async->prealloc_buf + async->buf_read_ptr);
+	comedi_buf_read_free(async, sizeof(sampl_t));
+	return 1;
+}
+
+int comedi_buf_put(comedi_async * async, sampl_t x)
+{
+	unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(sampl_t));
+
+	if (n < sizeof(sampl_t)) {
+		async->events |= COMEDI_CB_ERROR;
+		return 0;
+	}
+	*(sampl_t *) (async->prealloc_buf + async->buf_write_ptr) = x;
+	comedi_buf_write_free(async, sizeof(sampl_t));
+	return 1;
+}
+
+void comedi_reset_async_buf(comedi_async * async)
+{
+	async->buf_write_alloc_count = 0;
+	async->buf_write_count = 0;
+	async->buf_read_alloc_count = 0;
+	async->buf_read_count = 0;
+
+	async->buf_write_ptr = 0;
+	async->buf_read_ptr = 0;
+
+	async->cur_chan = 0;
+	async->scan_progress = 0;
+	async->munge_chan = 0;
+	async->munge_count = 0;
+	async->munge_ptr = 0;
+
+	async->events = 0;
+}
+
+int comedi_auto_config(struct device *hardware_device, const char *board_name, const int *options, unsigned num_options)
+{
+	comedi_devconfig it;
+	int minor;
+	struct comedi_device_file_info *dev_file_info;
+	int retval;
+
+	minor = comedi_alloc_board_minor(hardware_device);
+	if(minor < 0) return minor;
+	dev_set_drvdata(hardware_device, (void*)(unsigned long)minor);
+
+	dev_file_info = comedi_get_device_file_info(minor);
+
+	memset(&it, 0, sizeof(it));
+	strncpy(it.board_name, board_name, COMEDI_NAMELEN);
+	it.board_name[COMEDI_NAMELEN - 1] = '\0';
+	BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
+	memcpy(it.options, options, num_options * sizeof(int));
+
+	mutex_lock(&dev_file_info->device->mutex);
+	retval = comedi_device_attach(dev_file_info->device, &it);
+	mutex_unlock(&dev_file_info->device->mutex);
+	if(retval < 0)
+	{
+		comedi_free_board_minor(minor);
+	}
+	return retval;
+}
+
+void comedi_auto_unconfig(struct device *hardware_device)
+{
+	unsigned long minor = (unsigned long)dev_get_drvdata(hardware_device);
+
+	BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS);
+
+	comedi_free_board_minor(minor);
+}
+
+int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name)
+{
+	int options[2];
+
+	// pci bus
+	options[0] = pcidev->bus->number;
+	// pci slot
+	options[1] = PCI_SLOT(pcidev->devfn);
+
+	return comedi_auto_config(&pcidev->dev, board_name, options, sizeof(options) / sizeof(options[0]));
+}
+
+void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
+{
+	comedi_auto_unconfig(&pcidev->dev);
+}